Genetic Analysis of Syndromic and Nonsyndromic Patients With Craniosynostosis Identifies Novel Mutations in the and Genes.

Introduction: Craniosynostosis, the premature fusion of cranial sutures, is usually divided into 2 major categories: syndromic and nonsyndromic. Mutations in the , , , , and genes cause the common craniosynostosis syndromes Muenke, Crouzon and Crouzon with acanthosis nigricans, Apert, Pfeiffer, Saethre-Chotzen, and Craniofrontonasal. Overlapping features among craniosynostosis syndromes, phenotypic heterogeneity even within the same syndrome, especially in the case of Muenke syndrome, and inadequate clinical evaluation can lead to misdiagnosis, which molecular testing can help clarify.

Objective: The aim of this study is to investigate the underlying genetic cause in 46 patients with syndromic or nonsyndromic craniosynostosis by direct sequencing and/or microdeletion/microduplication analysis of the , , and genes.

Results: Genetic analysis identified 3 novel mutations, c.413T>C - p.(Leu138Pro) [p.(L138P)] in , the previously reported c.373G>A - p.(Glu125Lys) [p.(E125K)], and c.717dupA - p.(Leu240IlefsTer79) [p.(L240fs)] mutation in gene as well as 6 previously known mutations and a heterozygous gene deletion. The 2 novel mutations within gene arose de novo, but the novel mutation p.(L138P) within gene was inherited from the patient's father, who was found to be mosaic for the mutation. To our knowledge, this is the first case of mosaicism described for gene.

Conclusions: The contribution of molecular genetic analysis to the diagnosis of patients with syndromic craniosynostosis was useful because some were originally misdiagnosed. Conversely, thorough clinical evaluation can guide molecular testing and result in a correct diagnosis.